1. Field of the Invention
The present invention relates to a processing machine system and a method of positioning processing machines.
2. Description of the Related Art
In recent years, as a technique of manufacturing a semiconductor device, a fine patterning technique in which a mold is pressed against an uncured resin on a substrate to transfer a fine three-dimensional pattern formed on the mold onto the substrate is attracting a great deal of attention. This technique is called an imprint technique, which can form a fine structure on the order of several nanometers on a substrate. The photo-curing method, for example, is available as one of imprint techniques. In an imprint apparatus which adopts the photo-curing method, first, an ultraviolet-curing resin is coated (dispensed) on an imprint region on a substrate, and a mold is pressed against the resin. After the resin is cured upon irradiation with ultraviolet rays, the mold is released from the resin to form the pattern of the resin on the substrate.
An imprint apparatus is required not only to make the alignment error between a mold and a substrate fall within a tolerance on the order of several to several ten nanometers, but also to improve the transfer speed. In general, conventional exposure apparatuses such as a stepper and a scanner have a transfer speed and throughput higher than an imprint apparatus. To catch up with the throughput of the exposure apparatuses, a method of combining a plurality of imprint apparatuses into a cluster imprint system is available. In a cluster processing machine system, a plurality of processing machines are juxtaposed and manufacture devices, respectively, to ensure a given productivity and save space. Because cluster imprint systems especially use imprint apparatuses, each of which costs less than, for example, an immersion exposure apparatus, they offer an advantage in terms of cost as long as a large number of imprint apparatus can be arranged per unit area.
Unfortunately, juxtaposing processing machines often have a trade-off relationship with the transfer accuracy. That is, the vibration generated by one processing machine not only vibrates itself but will also vibrate other processing machines that are arranged around it through a supporting structure which supports the processing machine system. For example, during molding in which the mold is pressed against the uncured resin, the mold and the substrate maintain an accurate positional relationship in accordance with alignment conditions obtained in advance. However, when vibrational forces from other imprint apparatuses are transferred to a specific imprint apparatus, the interface at which the mold is in contact with the uncured resin becomes unstable, thus degrading the transfer accuracy. Japanese Patent Laid-Open No. 5-234865 discloses an apparatus which synchronously drives two stages so that reaction forces generated upon driving these stages cancel each other, in order to suppress vibration transfer between these stages through a base.
The apparatus disclosed in Japanese Patent Laid-Open No. 5-234865 employs a rigid body as a base which supports the stages, matches the times at which the stages start their acceleration/deceleration, and performs a synchronous operation so that the sum of the impulses of the times during which the stages accelerate/decelerate and the driving forces becomes zero. However, to set the sum of the impulses of the apparatuses to zero, it is necessary to take into consideration, for example, the number, positions, and rotational components of apparatuses, and the frequency components of generated vibrational forces, thus making it difficult to set the sum of the impulses to zero without adversely affecting other apparatuses. When a complex control system is provided to set the sum of the impulses to zero, it leads to an increase in cost.
As a method of suppressing vibration transfer between processing machines with no control system, a method of positioning a supporting structure so that vibrational forces generated by a plurality of processing machines do not adversely affect each other is available. However, simply setting large distances between the processing machines poses a problem resulting from a decrease in number of apparatuses arranged per unit area. A supporting structure which supports a plurality of processing machines is generally implemented by floor beams spaced apart from each other in two orthogonal directions. Each processing machine is placed on floor beams by fixing a pedestal provided in the processing machine to the floor beams. The bending rigidities of each floor beam are considerably different from each other in their longitudinal and widthwise directions, so the vibration transmission characteristics of this floor beam vary depending on the vibration direction, unlike a flat plate such as a base. Each beam has a low damping factor especially for vibration in the longitudinal direction, which is easily transferred. It is therefore desired to position processing machines in consideration of the vibration transmission characteristics of floor beams.